Internet Protocol (IP) is the backbone of modern networking and supported in most of the current telecommunications devices. IP is adaptable and has been extended to provide additional functionality.
IETF has defined private IP version 4 IPv4 address space in RFC 1918. This includes the following address spaces: 10.0.0.0-10.255.255.255, 172.16.0.0-172.31.255.255, 192.168.0.0-192.168.255.255. As the public IPv4 address space is nearing exhaustion, it is very common to use this private address space with Network Address Translation NAT to increase number of hosts that can be supported with limited number of public IPv4 addresses.
However, RFC 1918 specified address space allows only ˜17 million hosts behind single NAT. Historically this has not been a problem as networks so large have not existed. This is currently changing, as more and more operators are having more than 17 million simultaneous hosts connected into their network. In order to support a large number of customers, there needs to be multiple instances of private address spaces within a single operator domain (if the operator does not have enough public IPv4 addresses). This causes a need for cascaded NATs, which increase complexity and cost of network operations. IP version 6 IPv6 provides a large number of addresses, but IPv4 needs to be supported for a long time.
An address block spanning 240.0.0.0 to 255.255.255.255 (240.0.0.0/4), formerly designated as Class E is currently defined as being ‘Reserved’ in the Internet Assigned Numbers Authority IANA IPv4 address registry. There has been discussion on future use of this address space. The options include 1) keep the address space reserved for the future, 2) make the address space public, or 3) make the address space private. The third option would ease the problem of having multiple parallel private address spaces caused by too small address space defined by RFC 1918, and is proposed in IETF standardization. However, many existing implementations do not support or prevent use of this address space. An allocation of an address belonging to the 240.0.0.0 space for such implementation would result in failure.
Brief Description
Methods, apparatuses, and computer program products are now provided, which are characterized by what is stated in the independent claims. Some embodiments of the invention are described in the dependent claims.
According to an aspect of the invention, there is provided a method and apparatus for requesting assignment of a network address: a network address request with an indication of a specific network address space is generated in an address requesting entity to inform of capability of the address requesting entity to use a network address belonging to the specific network address space. The network address request is transmitted to an entity assigning network addresses. A response to the network address request is received, the response indicating the assigned network address belonging to the network address space.
According to another aspect, there is provided a method and apparatus for network address assignment: After receiving a network address request with an indication of a specific network address space, assignment of a network address belonging to the specific network address space is allowed in response to detecting the indication in the received network address request. A response to the network address request is transmitted, the response indicating the assigned network address. The specific network address space is to be understood broadly to cover some particular set of network addresses and is not limited e.g. to the IPv4 240.0.0.0/4 address space.
The invention and various embodiments of the invention provide several advantages, which will become apparent from the detailed description below. One advantage of an aspect of the invention is that it becomes possible to achieve backward compatibility with devices not supporting the specific network address space, such as the 240.0.0.0/4 IP address space. Problems caused by assigning addresses to conventional hosts not supporting use of addresses belonging to the specific network address space may be avoided. Network address assigning entities can thus assign addresses belonging to the specific network address space only for hosts verified to support the use of addresses belonging to the specific network address space.